avotto oj



H. B. JOHNSTON.

PlSTON AND PISTON RING.

APPucATmN man DEc.12. 1919.

1,333,023. Patented M....9,192o.

PSTON lliilll) PISTIl-RI-WG.

Application led Becenlber To all whom t may concern.'

Be it known. that l, l-lannr B. Joi-ins'ron, a citizen of the United States, residing at Seattle, in the county of King and State of Washington, have invented certain new and luseful Improvements in. Pistons and Pistonltings, of which the following` is a specilication.

T his invention relates to improvements in pistons and piston rings and more particularly to that type of piston for use in internal combustion motors; although it adapted for use .in any type of engine where a piston reciprocates within a cylinder and where it is necessary to prevent a fluid from passing from one end of the cylinder to the other, past the piston.

One of the objects of this invention is to provide a piston with au annular groove and a split ring` therefor in such proportions and relations that the fluid on one side of the piston will enter the space between the piston and cylinder wall, press upon the ring and force the same along an inclined wall of the piston, against the wall of the cylinder.

Another object is the provision of such a piston and ring construction which when applied to the internal combustion motor will, during the working:- stroke of the piston, carry the excess oil ahead of the ring. leavingonly the thin film thereon which. is necessary for proper lubrication. Thus is solved one of the most important problem of the internal combustion motor-that of' the prevention of over lubrication.

Still another object is the provision of such a piston and ringf construction which will have a tendency to center the piston in the cylinder thus preventing; the uneven erosion between the piston and cylinder and obviating the coinnion fault of the ordinary piston which wears the cylinder out of round. t

Another and still further object of iny invention is the provision of such a piston and ring construction in. which. not only is there a seal made between the ring and the cylind'errwall, but also a tight joint made between the ring and its groove, thus preventing the fluid from leaking around the back of the rin 9'.

All of these objects, I accomplish by pro- Viding in the piston body, an annular cir- Specicaten of Letters Patent.

Patented Idar. 9, tftl.

Serial No. 344,338.

` crunferential groove and a cothper'at-ing` rino',

the particular form of an embodiment of which is hereinafter set forth.

ln the drawings Figure l is a cross section of the pistou showing the rings in position.

Fig. 2 is a cross section of the ring.

Fig. 3 is a plan View of the ring.

The same reference characters refer to similar parts throughout the several figures of the drawing.

Referring now particularly to Fig. l, l() designates the piston, ll the groove for the split ring which operates during` the working stroke applied to an internal conibustion niotor, 2 the groove for the split ring which operates during the suction or intake stroke when applied to an internal combustion motor. ln the embodiment of my invention herein disclosed and shown in the accompanying drawings, the two upper and lower side walls of the groove are illustrated as being` divcrging, with relation. to each other, toward the outside of the piston` and one of these walls lies in a plane. The depth of the groove is great enough to permit the insertion of a ringwhich has a greater radial thickness than atrial thickness at its outer periphery, and to leave suliicient depth in addition to allow for a ,so-called carbon space.'J7 While one of the side walls of the groove is shown as lying in a plane, the essential features in. the construction are that the depth of the lgroove be enough greater than the width of the groove at the periphery of the piston to allow for the ring and carbon space and also that there be an inclined face on which the ring slides in its course toward the cylinder wall. 18 designates the split ring; in the groove 1l, and 14 the split ring in the groove 12, The rings l?, and 14C are identical in shape.

ln the consideration of the construction of the ring, let us consider the ring i3 as exemplary This ring, as shown, if applied to an internal combustion motor, would be the power stroke ring. As illustrated in this embodiment the ring has upper and lower side walls which diverge toward the outside of the ring, one of which lies in a plane. The heie'ht or axial thickness of the ring at the outside thereof is slightly greater than the width of the groove at the periphery of the piston. lhe same is true at the inner edge of the ring as compared With the inner or bottoni Width of the groove. The surfaces of the rings, as shown, hoivever, have the saine angle With relation to the axis of the piston as the angle of the corresponding part in the groove.

The upper surface l5 of the ring is the surface upon Which the gas or other fluid acts and its cooperation with its adjacent groove Wall is not so important as the cooperation between the other inclined ivall I6 and its corresponding groove Walh An important feature of the construction of rny ring is that its radial thickness is greater than its axial thickness at its periphery. The advantage of this construe tion Will be hereinafter brought out.

rIhe result of this construction of the ring is that when the ring' is installed in the groove, it extends beyond the peripheral surface of the piston and also leaves a carbon space la at the inside of the ring and the bottoni o the groove, as clearly shown in Fig. I. One of the purposes of this construction is to perinit free access of the gas to the top of the ring between the Wall of the cylinder and the piston, and thus force the ring' outward against the ivall of the cylinder. The purpose of the so-callcd carbon spacer` 19 to prevent cloggg'iiigjil of the ringv ivith carbon and also to furnish a space for oil.

I find that a piston and ring` constructed as above set forth renders an internal coinbustion motor Very c'liicient and I believe the reasons to be as follows:

As the gas froni the combustion chainber passes down the side. of the piston, it comes in contact with the upper surface l5 of the ringl 13 and somewhat with the outer surface 17. Since the arca oit the surface l5 is niuch greater than the arca of the s .'l ce IT, the result is that the rino; is pushed along the inclined side of the vgroove on its face lo and against the Wall of the cylinder. i'iother condition which I find is brought about is theproper sealingy between the surface lo ofthe ring and its bearing surface in the groove. This 'prevents the escape of gas underneath the ring which could not be avoided with a shalloiiT groove and corresponding radially thin rin e'.

I havealso found that in anY internal coinbustion-:niotor equipped with iny invention the action lof the gas forces the ring against the cylinder wall during the Working stroke in :such a Way as to reniove the excess oil from the cylinder, leaving' only a suiiicient quantity to properly lubricate the engine Without permitting 'excess oil to pass into the combustion 'chamber thereby causingl foulingof the -walls thereof and of the spark plug. valves, etc.

*I-have found further that in an internal combustion inotor equipped with iny invention, there is rnot the tendency for vthe cylinders to be worn out of round. rhis is due to the fact that during:r the WorkingA stroke, the piston is held centered by the action oi' the ring on the inclined wall oitl the piston. This is in eliiect a hollow cone, (the ring) hold ing within itself a solid cone (the inclined Wall of thc `groove). In this way the piston is held centered and excess ivear is pre Vented between the piston and cylinder ivall.

The ring' of niy invention is not solid bul split as shovvn at 18. In the drawings i have illustrated iny preferred cnilwdinicnl ivherein the ring has one split. I desire lo have it understood, hoivevcr. that thc split shown inerely illustrativo. and the invention is not limited to a ring` havia; a single split, since I have found that very ollicien results are obtained by in v invention havin;l

incre than one split in the ring. Neither do I liinit inysclt to the rig-ht angular split shovrn by the dr wing since any well linovfn or suitably shaped split can be used.

I have discovered that with niy in vcntion applied 'to an internal combustion niotor. the ainount of oil supplied to the -working surfaces of thc rings can be controlled by the width of the split in the ring.

In the herein described embodiment. of niy invention. I have slioixn two rings but it is to be understood that an)` desired nuniv ber inay be used.

In this invention tlnl resiliency of the ring is not n holly depended upon to expand the ring; as is ltoiunion in the art, since th'.` correlation and shape of the parts are such that the force of the lgas cupands the ring" and efficiently seals the space betiveen the piston and wall of the cylinder.

I have found that an internal combustion motor equipped with iny invention has such compression that it is uiniecessary to furnish an over-supply of jgasolcne in starting' the motor. This docs away with a fault very connnon in gasolene inet-ors since ivhcn an excess of ,gasolcne is present in tho combustion chamber, the lubricating' oil is .vaslnal an'ay by the gasolenc with a consequent scor' ing' of the ivall of the cylinder.

In the drawings it is to be noted that the rings are shown large relatively to the size of the piston. This is done in order to more clearly shovv the relative proportions of the dimensions of thc ring` and also of the groove and is not to be taken as al limitation since rings very inuch smaller niay be used as lone' as the relative prmziortions of the dimensions are maintained as herein described.

In iny preferred forni of piston. I construct the part nearest the combustion chainber as at 20 of less diameter than the part farthest away from the combustion chamber. at 2l. The purpose of this construction is to permit more clearance above the power stroke ringr to allow the ras to reach the ringA quite freely to vforce the saine against the lli] Wall of the cylinder' during the Working stroke, While still steadying the lovver or crank end ont the piston.

lt is obvious that many ininor changes in the construction and arrangement ct' the rings on the piston may be inade without de parting from the spirit oi the claims.

T his case is a division, in part, oit' my cepending application .Serial No. 307,338, liled June 28, 1919. 4

Having described my invention what l claim is:

l. In combination a piston having an annular groove, the side Walls of which are inclined divergently outward with relation to each other and Whose depth is greater than the axial Width out its opening, and split metallic piston ring in said groove, the radial thickness of which is greater than its axial thickness and Whose greatest axial thickness is slightly greater than the `width el" the groove at the periphery 01"' the piston.

2. ln combination a piston having an annular groove, the side Walls of which are inclined divergently outvvard with relation to each other, one ot which lies substantially in a plane, the depth of the groove being greater than the axial Width of its opening,

and a split metallic piston ring in said groove, the radial thickness of which is greater than its axial thickness and Whose greatest axial thickness is slightly greater than the Width of the groove at the periphery of the piston.

3. ln combination a piston having an annular groove, the side Walls ot which are inclined divergently outward ivith'relation to each other, the depth of which is greater than its axial Width at the periphery oli the metallic piston, and a split piston ring in said groove having its heightl at outer periphery greater than the greatest Width of the groove and having a radial annular thickness greater than its axial thickness at its' outer periphery.

4l. ln combination a piston having an an nular groove, the side Walls et which are inclined divergently outward with relation to each other, one side Wall lying substantially in a plane, the depth of the groove being greater than its axial Width at the periphery ot the piston, and a split metallic piston ring in said groove having its height at its outer periphery greater than the greatest 'Width of the groove and having a radial annular thickness greater than its axial thickness at its outer periphery.

5. ln combination, a piston having an annular groove, the depth of which is greater than its axial Width at the surface ot the piston, said groove having a side Wall inclined outwardly and away trom the pressure exerting fluid chamber, a split metallic piston ring in. said groove having a side `vall of the same slope as, and corresponding to, the inclined side Wall ci the groove, said ring being of greater radial Width than axial Width and ot such size relative to the groove that when in place it Will protrude beyond the surface ot the piston.

6. ln combination a piston having an annular groove, the depth ot which is greater than its axial Width at the surface of the piston, said groove having a side Wall inclined outwardly and away from the pres sure exerting fluid chamber, a split metallic piston ring in said groove having a side Wall 'of the same slope as, and corresponding to, the inclined side Wall of the groove, said ring being ci greater radial Width than theaxial Width and of such size relative to the groove that when in place it Will protrade beyond the suriiace of the piston and leave a carbon space at the bottom of the groove.

7. lfn combination, a piston having an annular groove, said groove having a Wall inclined outwardly and away troni the Working surface ot the piston, a split metallic piston ring the gij'oove, the radial thickness oit the rii'igl being greater than its axial thickness and having its opposite laces din vergent relative to each other, thesides olf the groove having portions which coact With the divergent faces to hold the ring so that its outer periphery will be beyond the periphery oi the piston.

ln testimony whereof l aliix my signature.

Hilillll'( B. JOHNSTON, 

